Hydraulic fluid volume compensator



Aug.'21, 1945.' H. R. ELLlNwooD y 2,333,180

HYDRAULIC FLUID VOLUME COMPENSATOR Filed Nov. 24, 1942 2 Sheets-Sheet l Aug. 21, 1945. H. R. ELLlNwooD 2,383g' HYDRAULIC FLUID VOLUME COMPENSATOR Filed Nov. 24, 1942 2 sheets-sheet 2 w w m /FOV 7 x m f 5 5 Patented Aug. 21, 1945 HYDRAULIC FLUID VOLUME COMPENSATO Herman Ray Elllnwood, Burbank, Calif., assigni or to Adel Precision Products Corp., a corporation o! California Application November 24, 1942, Serial No. 466,183 y 6 Claims. This invention relates to hydraulic motor systems, particularly hydraulic systems for operating the controls and component mechanisms of aircraft and the like.

A primary' object of my invention is to provide a hydraulic iluid volume compensator which in a most reliable and emcient mannerwili fully tion and volumetric variations'of the hydraulic iluid in a hydraulic system to insure the presence in all working parts of the system of therequisite amount of hydraulic iiuid for s, reliable operation of the system at all times.

Another object oi my invention is to provide an improved hydraulic motor system embodying a volume compensator oi the character described which is inoperative while the system is in operation and rendered operative upon cessation oi operation of the system. A A iurther object of my invention is to provide an emcient manually operable motor system such as described in which afiow reversing pump unit is operable for directing lluid tojactuate a i hydraulic motor in either direction.' and thevolume compensator of my invention is rendered inoperative by and upon the act of` releasing from a normally locked position a lever for actuating 'the pump unit, and rendered operative immediately following the locking of said lever and the cessation or operation of the pump unit.

Yetfanother object of my invention is to provide a hydraulic iluid volume compensator in which a compensator ch'amber and a diaphragm means therein, together with a valve means. arearranged so that there is formed an' expansible and contractible reservoir means and a, pressure compartment, said reservoir means being connected through the valve means to both sides of-hydraulic system, and said pressure compartment containing a. fluid'under a pressure to which the diaphragm means is responsive whereby hydraulic iluid will be forced from as well as into said reservoir means incident to volume variations in the system caused by thermal expansion and contraction of the fluid therein as well as by leakage, the said valve means being arranged to render the compensator inoperative upon operation of the system and operative when the system ceases to operate. f

Yet' another objectof my. invention is Ato vprovide a volume compensator oi the character described in which 'a chamber and a, diaphragml means are arranged to denne expansible and contractible compartments, two of which arevreservoir compartments adapted to be connected to the `hydraulic lines oi both i compensate for thermal expansion and'contracsides or a hydraulic motor system and one of which, located between saidl two compartments, contains a compressible fluid under a predetermined pressure to which the dia-j phragm means is responsive as well as to the-fluid pressure 'in said system lines. thereby insuring the flow of fluid into and from said reservoir compartments to maintain the proper amount of fluid throughout the system.

With the'ioregoing objects in view. .together with such other objectsand advantages asl may subsequently appear, the invention resides in the parts and in the combination, construction and arrangement of parts hereinaiterdescribed and claimed, and illustrated by way of example in j the accompanying drawings, in which:

Fig. 1 is a diagrammatic view' of a .hydraulic system embodying my invention:

Fig; 2 is a diagrammatic view of a modiiled form of system embodying my invention. l '1 Fig. la is an end elevation of the `upper DGIT of the structure shown in Fig. 1 looking from right to left as indicated by the arrows la on Fig.. 1`

but 'when the locking means f mentality Reierringto the drawings more specifically, itv is seen with 'reference to Fig. 1 that a hydraulic system embodying my invention `generally in" cludes a hydraulic pump unit A operable ,man-` ually to direct hydraulic iluid through lines B and C ,to opposite sides oi a motor D employed, for

example, to actuate the control elements or coxn-4 ponent mechanisms oi an aircraft. A compensating accumulator unit E is connected to the lines B and C through the instruof valve means F which is controlled by an operating means G operatively associated with a lever locking means H of a lever J for operating theapump unit. This arrangement is such that' the' operation oi releasing the locking lmeans H causes the valve means A1 to be closed and-the compensating unit E to yloe renderedinoperative is locked and the pump unit thereby made inoperative, the valve. in case of expansion of the fluid in the system the iluid will be relieved to the compensator unit E 'and'in case of contraction or leakage of the iluid in either or both. sides of the system, the compensator unit cally force liluid into the system to compensate for the 'loss oi' volume resulting from such contraction or leakage. f

, As here shown the'pump unit includes a cylinder I in whicna piston 2 is reciprocable to force fluid from the cylinder to operate the motor unit D in either direction. -The lever J is suitably vfulcrurne'd on'a pivot one end as at I, and has a pin will automatii and slot connection l with the lpiston 2, there being slots and 8 in t'h'e cylinder I to accomodate the lever. The motorl unit as here shown includes a cylinder 1 having a reciprocable piston 8 therein and provided with a'drive means 9 operated by arack Ill formed on the piston.

As here provided the locking means H for lever J includes a notched quadrant II, a locking rod I2 reciprocally supported on thelever to slide longitudinally therealong and having a bolt portion I3 thereon adapted to be engaged in the notches in the quadrant II, This locking rod I2 is normally urged into locking position by means of a spring I4 in the valve operating means G and is depressed to release the lever, which has a slotted part in a slidable relation to the pivot 3. On depressing the locking rod I2 the inner end I5 thereof forces a plunger I6 inwardly in a support I1 therefor against the action of t'he spring The spring I4 ,is contained in a tubular guide member I8 slidable in the support I'I and receiving theginner end of the plunger I A cross head I9 on the inner end of the guide member i8 is provided with a guide pin 20 slidable in a bore 21| of a Valve body member 22. In this body member 22 are valve chambers 23 and 26 having valve seats 25 and 26 between ports 21 and 28. Poppet valves 29 'and 30 are mounted in' the chambers 23 and 2d respectively and have their stems 3i fixed to the cross head I9. Springsz for` thesefvalves normally hold the valves open and assist the spring I4 in urging the lever-locking means into locking position.

A fluide line 33 connects line B with the valve chamber 23 through one of t'h'e ports 21 whereasa fluid line 36 connects the line C with thevalve chamber through the other port 21. The ports 28 are provided `for affording communication of the valve unit with the compensating-unit'E.

In accordance with' my invention the compensator unit is designed toprovide a, uid filled expansible and contractible reservoir means and a pressure means therein. The reservoir means is adapted to be connected to both sides of the system through the valve means F for receiving iuid from and supplying fluid to said sides oi' the system. The pressure means, for example,l may be provided as a compartment containing air trapped therein under a. predetermined pressure such that the reservoir means is responsive thereto as well as to the pressure of the hydraulic fluid in the system. The arrangement is such that when the system is not under operation the valve means is opened and if the fluid in any part of the system`contacts or leaks out, thereby reducing the volume of the operating fluid, the pressure of the hydraulic fluid in the reservoir means of the com- .pensatorl unit is reduced below that of the air pressure in the pressure compartment and the reservoir means then contracts and forces fluid therefrom into the system in full compensation for the volume loss caused as aforementioned. In case of expansion of iluid in any part of the system the resultant increased pressure causes4 the reservoir means to expand as permitted by the compression ofthe air in the pressure compartment, whereby the excess volume is relieved from' the system into said reservoir means and an effective volume compensation is thus produced throughout the system.

As shown in Fig. 1 .the compensator means E includes a closed chamber 35 having diaphragms 36 and 31 arranged therein to define expansible and contractible reservoir compartments 38 a'nd 39 separated by a pressure compartment 4.0 which fills in th'e space between said reservoir compartments. Lines 4I and 42 connect the ports 28 in the valve body member 22 with the reservoir compartments 38 and 39 respectively. This arrangement constitutes a reservoir means in accordance with this invention, as hereinbeiore noted.

The pressure compartment is .provided with a valved inlet 43 whereby the compartment may be supplied with a compressible iluid such as air under a predetermined pressure to which' the diaphragms 3B and 31 will be responsive incase the iiuid in the system contracts or leaksout to an extent that the pressure of such fluid is -below that of the air in the pressure compartment.

It is now apparent that when the operator depresses the rod I2 for releasing the locking means H for the lever J, the inner end I5 of said rod will depress the plunger IB, and through the spring I4 likewise depresses the tubular guide I8, cross head I9, and the valves 29 and 30, thereby closing the valves. It should be noted that before the locking bolt I3 on the rod I2 releases the lever J the Valves 29 and 30 will be seated to insure that the valves are closed before the pump unit A is operated, Thus the compensator unit E is rendered inoperative during operation of the pump and motor units.

When the operator releases the locking rod I2 the locking bolt I3 thereon locks the lever to the quadrant and the valves 29 and 36 are released so that the springs 32 will unseat them, thereby rendering the compensator unit rE operable. At this time if the hydraulic iluid in the system contracts or leaks out to the extent that the pressure thereof is below that of the air iii the pressure chamber 40, the diaphragms 36 and 31, either one or both thereof, depending on whether the pressure reduction occurs in one or both sides of the system, will respond to the airpressure so that iluid will be forced into the system from either or both oi the compartments 38 and 39 into the system tocompensate for the volume loss due to said contraction or leakage.'

It is to be observed that the inner end portion i5 of the locking rod i2 terminates in a curved surface which affords a continuous contact of said rod with the plunger I6 of the valve means in `all the operative angular'.positionsl of the swingable lever J.

Itwill also be seen that the spring opposed slidable rod I2 carried by the lever is slidable therealong by a hand of the operator which is thereupon positioned to Swing said lever while maintaining said rod in the position to which it has been slid. Therefore the operator can, by the use of single hand swing the lever through its l compartment 40 then compressing. This allows the excess of uid produced by such expansion to be relieved into the compartments 38 and 39 or ,g

either thereof and the desired volume is provided in both sides of the system to insure a proper operation thereof.

As shown in Fig. 2, a modified form of my invention includes a pump unit A', lines B' and C' leading therefrom to a motor unit D', a modified form of compensating accumulator unit E', a

- partments It.

valve means, F', a valve operating means G', a lever locking means H and a lever J With the exception of th'e compensator unit E all oi' the other elements oi this system are identical with the corresponding elements. of the rst described system as shown in'Flg. 1.

In this inodiiled form the unit E Aincludes a -chamber ll having a single diaphragm 5I therein defining a reservoir means such as` the 'compartment l2 and a pressure means suchas the comvalve chambers and I1 containing the valves Il and l. This makes the two lines B' and C' ci the system subject to communication through the valve means with the single reservoir compartment I2.

The pressure compartment Il has a valved inlet Il whereby it may be charged with. air under a predetermined pressure to which the -dia- Dhrm il reponsive when thermal contraction of the duid inthe system takes place', for forcing `iluiei from the reservoir chamber into the system in the manner as in theother form or my invention. In ease of thermal expansion of the iiuid in the system the reservoir compartment 52 will expand by action of the diaphragm and compensate for the excess pressure and volume.

Iclaim:

l. In a hydraulic motorsystem, a pump unit, a

motor unit, hydraulic lines ior conducting fluid between said units. to operate said motor unit, a'

lever for operating s aid pump unit, a lever locking means including a rod carried by said lever vand. slidable longitudinally therealong, a hydraulic iluid volume compensating means connected withv lines. a valve means for controlling the operation of said compensating means. and means operating responsive to the release oi` said locking means by a sliding movement oi said rod, for closr portions, a lever swingably mounted between said piston heads and operatively connected with them to reciprocate them simultaneously, means car-- ried by said lever to release and to lock it in cluding a manually operable rod slidable lengthwisetherealong, a pivot to which one end portion oi said lever is tulcrumed and with which said rod is slidably connected, a toothed locking segvment for said'lever into and out or engagement l with which said rod is manually movable owing toits said slidable mounting, a motor unit, drive a" hydraulic compensating means'connected meansconnected therewith and operable in opposite directions by fluid pressure delivered to said motor, a hydraulic line leading from one end por- The reservoircompartment 52 is connectedby branched lines M and l! with the Y means, is manipulated to lock said ,lever and render the pump cylinder inoperative, the` inner .end .portion of said slidable rod having a curved surface which affords a continuous contact 'with' a part of said valve means in all positions of said swingable lever, said valve means including a spring which maintains it in continuous contact with saidcurved surface of said rod.

means including a reciprocatory plunger which is urged in one direction by said spring' and is at times moved in the opposite direction by the acti'on thereon of said curved portion of said rod.

4. In a hydraulic motor system, a pump cylin` der having a piston head in each of opposite end portions, a lever swingably mounted between said piston heads and operatively connected with them to reciprocate them simultaneously, means carried by said lever to release and to lock it inv vment for said lever into and out of engagementwith which said rod is manually movable owing cluding a manually operable rod slidable lengthl wise therealong, a pivot to which one end portion of said lever is fulcrumed and with which said rod is slidably connected, a toothed locking segto its said slidable mounting. a motor unit, drive means connected therewith and operable in opposite directions. by fluid pressure delivered to said motor, a hydraulic line leading from' one end portion of the aforesaid piston cylinder to said motor unit to move said-drive. means in one direction, a hydraulic line leading from the opposite 4end portion of said piston cylinder to said motor unit to move said drive means in the opposite direction, a hydraulic compensating means connected with said lines, a valve means for controlling the operation of said compensating means, and means operating in response to the sliding movement of said rod for closing said valve means and rendering the compensating means` inoperaand for opening said valve means and rendertive, ing ,the compensating means operative when thelocking means is manipulated to lock said lever and renderv the pump cylinder inoperative, said" 5. In a hydraulic motor system, a pump unit,

a mot'or'unit, hydraulic lines for conducting fluid between said units to operate said motor unit, a

lever for operating said pump unit.- a lockingv means for said lever including a spring opposed rod carried by said lever and slidable longitudinally therealong by a hand of the operator which is thereupon .positioned to swing said lever while tion of the aforesaid piston cylinder to saldrmotor unit to move said drive means in one direction, a hydraulic line leading from the opposite end portion of said piston cylinder to said motor unit to4 oppositeV direction,"

ove said drive means in the with said lines, a valve means for controlling the operation .of said compensating means, and means operating in response to the sliding movement of said rod for closingyaaid valve means and rendering the compensating meansinoperative, and for opening said lvalve means and renderingthe -compensating means operative when the locking maintaining said has been slid. in

rod in the position to which it which position said rod unlocks said lever, a hydraulic iiuid volume compensation means connected withV said lines. a valve means for controlling the operation of said compensating means, and means operating in response to the aforesaid slidingV movement of said rod for closing said valve means thereby rendering the compensating means inoperative, and operable by the spring impelled action offsaid rod to lock said lever and simultaneously render the compensating.

means operative.

6. In a hydraulic motor system, a .pump unit. a motor unit, hydraulic lines for conducting fluid between said units to operate said motor unit, a lever for operating said pump unit, a spring opposed iockingrneans carried by said lever and movable in relation thereto by a hand of the operator which is at the same time positioned to lock said lever and simultaneously renderth compensating means operative.

HERMAN RAY ELLINWOODQ.

oi' said spring opposed means for .closing said valve means, thereby rendering the compensating' means inoperative, and operable by the spring to. 

